Unified frame for semiconductor material handling system

ABSTRACT

The present invention is a unified spine structure that EFEM components, such as a wafer handling robot and a SMIF pod advance assembly, may mount to. The frame includes multiple vertical struts that are mounted to an upper support member and a lower support member. Structurally tying the vertical struts to the support members creates a rigid body to support the EFEM components. The vertical struts also provide a common reference that the EFEM components may align with. This eliminates the need for each EFEM component to align with respect to each other. Thus, if one EFEM component is removed it will not affect the alignment and calibration of the remaining secured EFEM components. The unified frame also creates an isolated storage area for the SMIF pod door and the port door within the environment that is isolated from the outside ambient conditions.

CLAIM OF PRIORITY

[0001] This application claims priority from provisional applicationentitled “UNIVERSAL MODULAR PROCESSING INTERFACE SYSTEM”, ApplicationNo. 60/316,722, filed Aug. 31, 2001, and which application isincorporated herein by reference.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] 1. U.S. Patent Application No. ______, filed ______, entitled“WAFER ENGINE”; and

[0003] 2. U.S. Patent Application No. ______, filed ______, entitled“SEMICONDUCTOR MATERIAL HANDLING SYSTEM”.

FIELD OF THE INVENTION

[0004] The present invention generally relates to a wafer transfersystem. More particularly, the present invention is a unified, scalableframe or structure that equipment front end module (EFEM) componentsmount to, and wafer engine for transferring wafers.

BACKGROUND OF THE INVENTION

[0005] Standard Mechanical Interface Pods (SMIF pods) are in generalcomprised of a pod door which mates with a pod shell to provide a sealedenvironment in which wafers may be stored and transferred. One type ofpod is a front opening unified pod, referred to as FOUP 10, in which thepod door is located in a vertical plane, and the wafers are supportedeither in a cassette mounted within the pod shell, or two shells mountedin the pod shell.

[0006] During the fabrication of semiconductor wafers, the SMIF pods areused to transport the workpieces between various tools in the wafer fab.These tools include process tools for forming integrated circuitpatterns on the wafers, metrology tools for testing the wafers, sortersfor sorting and rearranging the wafers within one or more SMIF pods, andstockers for large scale storage of SMIF pods. The tools are generallylaid out in a wafer fab in one of two configurations, a bay and a chaseconfiguration or a ballroom configuration. In the former arrangement,only the front of the tool including the workpiece I/O port ismaintained in the clean room environment of Class-1 or better. In theballroom configuration, the tools are arranged in clusters according tothe operations they perform, with the entire tool being maintained inthe clean room environment of Class-1 or better.

[0007] Tools within a wafer fab include a front-end interface whichhouses components that facilitate and monitor the transfer of workpieces(i.e. wafers) between the pods to the tools. A conventional front endunit or equipment front end module (EFEM) 20 is shown in FIGS. 1-2.EFEMs 20 are generally constructed at a tool manufacturer and thenshipped to a wafer fab.

[0008] An EFEM 20 generally includes a housing 22 which is fixed to thefront of the tool and a workpiece handling robot 24 mounted within thehousing and is capable of x, r, θ, Z motion to transfer workpiecesbetween the workpiece carriers, tool and other front end components. Therobot 24 is generally mounted with leveling screws that will allow theadjustment of the planarity of the robot 24 once the EFEM 20 isconstructed and affixed to a tool.

[0009] In addition to a robot 24, the EFEM 20 generally includes one ormore prealigners 26 for performing the operation of wafer centeridentification, notch orientation, and indocile mark reading. Theprealigner(s) 26 are commonly bolted into the housing 22 with levelingscrews allowing the planarity of the prealigner(s) to be adjusted oncethe EFEM 20 is constructed and affixed to a tool.

[0010] An EFEM 20 further includes one or more load port assemblies 28for receiving a workpiece carrier, opening the carrier, and presentingthe workpiece to the robot 24 for transfer of the workpieces between thecarrier, and other processing tools. For 300 mm wafer processing, avertically oriented frame, commonly referred to as a Box Opener-LoaderTool Standard Interface (or “BOLTS” interface), has been developed bySemiconductor Equipment and Materials International (“SEMI”). The BOLTSinterface attaches to, or is formed as part of, the front end of a tool,and provides standard mounting points for the load port assembly toattach to the tool. U.S. Pat. No. 6,138,721, entitled “Tilt and Go LoadPort Interface Alignment System,” which is assigned to the owner of thepresent application and which is incorporated by reference in itsentirety herein, discloses a system for adjusting a load port assemblyto the proper position adjacent a BOLTS interface and then affixing theload port assembly to the interface.

[0011] Once the robot 24, the prealigners 26 and load port assemblies 28have been mounted to the housing 22, the EFEM 20 is shipped to the waferfab and affixed to a tool within the fab. After being properly securedto the tool, the EFEM components are leveled within the housing 22 viathe leveling screws, and the robot 24 is then taught the acquisition anddrop-off positions it will need to access for workpiece transfer betweenthe load port assemblies, the prealigners and the tool. A system forteaching the various acquisition and drop-off positions for the robotwithin the tool front end is disclosed in U.S. patent application Ser.No. 09/729,463, entitled “Self Teaching Robot,” which application isassigned to the owner of the present application and which applicationis incorporated by reference herein in its entirety. Once the robotpositions have been taught, side panels are attached to housing 22 tosubstantially seal the housing against the surrounding environment.

[0012] For example, conventional EFEMs include many separate andindependent workpiece handling components mounted within an assembledhousing. The housing 22 includes a structural frame, bolted, constructedor welded together, in a plurality of panels affixed to the frame. Afterthe housing 22 is assembled, the EFEM components are fixed to thevarious panels. It is a disadvantage to prior art EFEMs that the overallsystem tolerances are compounded with each frame member, panel andcomponent connection. The result is that the assembled EFEM componentsare poorly aligned and need to be adjusted to the proper position withrespect to each other. The robot 24 must also be taught the relativepositions of the components so that the EFEM components can interactwith each other. This alignment and teaching process must take placeevery time there is an adjustment to one or more of the EFEM components.

[0013] A further shortcoming of the prior art is that EFEM componentsare frequently made by different suppliers, each with its own controllerand communication protocols. Steps must be taken upon assembly of theEFEM so that the controllers of each component can communicate with eachother and the components can interact with each other. The separatecontrollers also complicate maintenance and add to the parts andelectrical connections provided in the EFEM. Further still, especiallyin a ballroom configuration, the conventional EFEM takes up a largeamount of space within a Class-1 cleanroom environment where space is ata premium.

[0014] Today's 300 mm semiconductor EFEMs are comprised of several majorsubsystems including SEMI E15.1 compliant load port modules (typically2-4 per tool). For example, an EFEM may consist of a wafer handlingrobot and a fan filter unit mounted to a structural steel frame, andhave panels to enclose the wafer handling area between the load portsand the process tool. The combination of these components provides ameans of transferring wafers to and from a FOUP 10, and between the FOUPand the process tool wafer dock(s). FOUPs 10 are manually loaded viaoperators or automatically loaded via an automated material handlingsystem (AMHS) delivered to and taken from the Load Port. IndustryStandards have been created to allow multiple vendors to provide theLoad Port, FOUP 10, or other EFEM components to be integrated as asystem.

[0015] The Load Port component provides a standard interface between theAMHS and the wafer handling robot in the EFEM. It provides astandardized location to set the FOUP 10, docks the FOUP 10 to seal thefront surface, and opens and closes the door to allow access to thewafers in the FOUP 10. The dimensions of this unit are all specified inSEMI E15.1.

[0016] The Load Port attaches to the Front End via the Bolts Interfacewhich is defined by SEMI E-63. This standard defines a surface andmounting holes to which the Load Port attaches. It is defined to startat the fab floor and goes as high as 1386 mm from the floor and is about505 mm wide per Load Port. As a result, the load port completely blocksoff the process tool from the operator aisle in the fab. SEMI E-63 alsodefines load port dimensions on the tool side to ensureinterchangeability with a variety of robot manufacturers.

[0017] The primary functions of the load port include accepting a FOUP10 from and presenting to a FOUP 10 to the Fab AMHS, moving the FOUP 10towards and away from the port seal surface (docking/undocking), andopening and closing the FOUP door. In addition, it must performfunctions such as locking the FOUP 10 to the advance plate, lock andunlock the FOUP door, and a variety of lot ID and communicationfunctions. Per SEMI E15.1, all of these functions are contained in asingle monolithic assembly which is typically added or removed from thetool front end as a complete unit.

[0018] The load port must be aligned with precision to the wafer robot.If there are multiple load ports in the system, they must all presentthe wafers in level parallel planes. Typically, the Load Ports provideseveral adjustments to planarize the wafer in the FOUP 10 with therobot. In order to minimize time spent calibrating the robot to each ofthe 25 wafer positions in each of the FOUPs 10, specialized tools andalignment fixtures are used in conjunction with all of the adjustments.If a load port is swapped out with a new one, the calibration procedurecan be quite lengthy.

[0019] In addition to aligning the robot to the wafers positions, thedoor mechanism must also be aligned with the door opening and the doorseal frame. Again, this is typically performed with alignment fixturesand tools either on the tool front end or off line.

[0020] The robot must also be leveled and aligned with one or more tooldrop off point. This is typically done manually by teaching the robotthe position and making planarity adjustments either on the front end orthe tool.

[0021] It is the combination of all of these relationships between thetool, the robot, and the FOUPs 10 which make setting up a tool front endso time consuming. All of the components are typically attached to arelatively low precision frame, and adjustments are used to compensatefor it. The load ports are mounted to the front surface, the robot tothe base, the fan/filter unit (FFU) to the top, and skins on all otheropen surfaces to complete the mini-environment enclosure.

[0022] It would be advantageous to minimize the adjustments between thecomponents and reduce the overall time required to align the load port.The present invention provides such an advantage.

SUMMARY OF THE INVENTION

[0023] One aspect of the present invention is to provide a unifiedstructure or frame that precisely ties many critical EFEM componentstogether. In one embodiment, the frame serves as a single reference foraligning the interior and exterior EFEM components. In anotherembodiment, the interior and exterior EFEM components are aligned inrelation to each vertical strut of the frame.

[0024] Another aspect of the present invention is to provide a unifiedstructure or frame that is scalable in size. In one embodiment, theunified structure includes vertical struts secured to an upper and lowersupport member. The number of vertical struts and the length of theupper and lower support member depends on the number of I/O ports withinthe EFEM. Similarly, the size and spacing of the vertical struts and thesupport members may vary to accommodate 200 mm wafers, 300 mm wafers,and 400 mm wafers.

[0025] Yet another aspect of the present invention is to accurately andprecisely locate the front load components with respect to each other.Preferably, this calibration process is accomplished with a minimumnumber of adjustments. In one embodiment, all the interior and exteriorEFEM components are precisely tied to the unified frame such that theyshare common reference points.

[0026] Yet another aspect of the present invention is to provide aunified frame that segregates and isolates the port door/carrier doorassembly from the many of the interior EFEM components. In oneembodiment, the port door/carrier door assembly is lowered into aseparate air flow/storage area located within the mini-environment. Thestorage area prevents particles created by, for example, a waferhandling robot, from contaminating the assembly.

[0027] Still another aspect of the present invention is to provide awafer carrier docking/interface plate that can be easily removed fromthe EFEM to access the interior of the EFEM. In one embodiment of thepresent invention, the removable plate is manufactured from atransparent material so that a user may observe anyproblems/malfunctions that occur within the mini-environment.

[0028] Still another aspect of the present invention is to decrease thefootprint of the EFEM. In one embodiment, the EFEM is supported by arolling stand whereby the bottom surface of the EFEM is raised off thefloor of the wafer fab. The area between the wafer fab floor and theEFEM may serve as a maintenance access port to the processing tool, oran area to place auxiliary compartments.

[0029] Still another aspect of the present invention is to provide awafer engine for transferring wafers. In one embodiment, the waferengine may perform a number of inspection, marking, and metrologyfunctions, eliminating the need for a separate processing station.

[0030] Still another aspect of the present invention is to provide awafer engine that may transfer wafers within the reduced footprint ofthe EFEM. In one embodiment, a wafer engine includes a linear drive formoving the wafer along a x-axis, a vertical drive for moving the waferz-axis, a radial drive for moving the wafer along a radial axis, and arotational drive for rotating the vertical and radial drive about atheta axis.

[0031] A further aspect of the present invention is to provide localfiltering for various particle generating mechanisms on the waferengine. In one embodiment, a fan/filter unit is mounted to the radialdrive to capture particles created by the radial drive. In anotherembodiment, an exhaust system creates an air flow through the verticaldrive to capture any particles created by the vertical drive. Theselocalized fan/filter units attempt to control particles created by thewafer engine by exhausting the particles into a “dirty-air” environment,or by first filtering the air before it is exhausted back into a “cleanair” environment.

[0032] Still another aspect of the present invention is to provide awafer engine that has dual swap and align-on-the-fly capabilities. Inone embodiment, the wafer engine has a rapid swap radial drive, orbuffer capability, to simultaneously store and transfer two wafers. Inanother embodiment, an upper end effector may rotate and align a firstwafer while a second wafer is stored and/or transported by a lower endeffector.

[0033] Still another aspect of the present invention is to provide awafer engine that has a removable/interchangeable slide body mechanism.In one embodiment, the slide body mechanism includes integratedprocessing tools such as an OCR reader, an aligner, an ID reader, or ametrology tool. A removable slide body mechanism allows a wafer fab toincorporate the same wafer engine throughout whereby only the slide bodymechanism must be customized to each individual process station.

[0034] Yet another aspect of the present invention is to provide a waferengine having a vertical drive located above the theta drive. Such avertical drive is located substantially within the FOUP 10 area andminimizes the footprint of the wafer engine.

[0035] The present invention provides all of these advantages.

DETAILED DRAWINGS OF THE PRESENT INVENTION

[0036]FIG. 1 is a perspective view of a conventional front end assemblyin accordance with the prior art;

[0037]FIG. 2 is a top view of the front end assembly shown in FIG. 1;

[0038]FIG. 3 is a side view of a conventional front end assembly inaccordance with the prior art;

[0039]FIG. 4 is a perspective view of an embodiment of the spinestructure, according to the present invention;

[0040]FIG. 5 is a partial exploded view of the spine structure shown inFIG. 4;

[0041]FIG. 6 is a perspective view of an embodiment of a FOUP dockinginterface, according to the present invention;

[0042]FIG. 7 is a partial exploded perspective view of an embodiment ofthe spine structure and front end load components, according to thepresent invention;

[0043]FIG. 8 is a perspective view of an embodiment of a wafer enginemounted to the spine structure, according to the present invention;

[0044]FIG. 9 is a perspective view of an embodiment of a wafer enginedrive rail mounted to the spine structure, according to the presentinvention;

[0045]FIG. 10 is a side view of an embodiment of the front end loadinterface, according to the present invention;

[0046]FIG. 11 is a partial exploded view of another embodiment of theintegrated mini-environment and structure, according to the presentinvention;

[0047]FIG. 12 is a side view of the integrated mini-environment andstructure as shown in FIG. 11;

[0048]FIG. 13 is a partial perspective view of an embodiment of thebackbone structure according to the present invention;

[0049]FIG. 14 is perspective view of still another embodiment of theintegrated mini-environment and structure, according to the presentinvention;

[0050]FIG. 15 is an end view of the integrated mini-environment andstructure shown in FIG. 14;

[0051]FIG. 16 is a partial exploded view illustrating an embodiment ofthe unitized frame of the integrated mini-environment and structureshown in FIG. 15;

[0052] FIGS. 17A-17B; FIG. 17A is a top view of an embodiment of aconventional wafer handling robot; FIG. 17B is a top view of the waferhandling robot shown in FIG. 17A with the end effector extended,according to the prior art;

[0053]FIG. 18 is a perspective view of an embodiment of a rapid swapwafer engine, according to the present invention;

[0054]FIG. 19 is a perspective view of the wafer engine shown in FIG. 18illustrating several of the components of the drive mechanisms and thevertical column and the slide body mechanism;

[0055]FIG. 20 is a perspective view of another embodiment of a waferengine, according to the present invention;

[0056]FIG. 21 is a perspective view of the wafer engine shown in FIG.18, illustrating the air flows created by the fan/filter units;

[0057] FIGS. 22A-22D; FIG. 22A is a perspective view of still anotherembodiment of a wafer engine equipped with a wheeled aligner and an IDreader on the slide body mechanism, according to the present invention;FIG. 22B is a top view of the wafer engine shown in FIG. 22A; FIG. 22Cis a slide view of the wafer engine shown in FIG. 22A; FIG. 22D is arear view of the wafer engine shown in FIG. 22A;

[0058]FIG. 23 is a perspective view of an embodiment of the upper endeffector shown in FIG. 22A;

[0059] FIGS. 24A-24C; FIG. 24A is a cut away view of an embodiment ofthe wheeled end effector aligner illustrating a wafer supported by thepad; FIG. 24B is cut away view of the wheeled end effector aligner inFIG. 24A illustrating the wafer lifted off the pad and supported by thewheel; FIG. 24C is cut away view of the wheeled end effector alignershown in FIG. 24A illustrating the wafer being released by the wheel andset back down on the pad;

[0060]FIG. 25 is a perspective view of yet another embodiment of thewafer engine, according to the present invention;

[0061] FIGS. 26A-26B; FIG. 26A is a perspective view of anotherembodiment of the radial drive; FIG. 26B is still another embodiment ofthe radial drive;

[0062] FIGS. 27A-27B; FIG. 27A is a plan view illustrating the reach andswing clearance advantage of the wafer engine according to the presentinvention; FIG. 27B is plan view of a conventional linear slide robotillustrating the minimum clearance and maximum reach required;

[0063]FIG. 28 illustrates an example motion sequence for the rapid swapslide body with off center rotation axis, according to the presentinvention;

[0064] FIGS. 29A-29D; FIG. 29A is a perspective view of an embodiment ofthe front end load interface, according to the present invention; FIG.29B is a front view of the integrated system shown in FIG. 29A; FIG. 29Cis a side view of an embodiment of the front end load interface shown inFIG. 29A; FIG. 29D is a plan view of an embodiment of the front end loadinterface shown in FIG. 29A;

[0065] FIGS. 30A-30B; FIG. 30A is a perspective view of an embodiment ofthe integrated system mounted to a processing tool; FIG. 30B is a sideview of the integrated system shown in FIG. 30A; and

[0066]FIG. 31 is a side view of the integrated system shown in FIGS.30A-30B, illustrating how the integrated system frees up space forAutomated Material Handling System (AMHS) buffering.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0067] The present invention will now be described with reference toFIGS. 4-31, which relate generally to a wafer transfer system. Thepreferred embodiments of the present invention are used for 300 mmsemiconductor wafer fabrication. The present invention may also be usedin the fabrication of workpieces other than semiconductor wafers, suchas for example reticles, flat paneled displays and magnetic storagedisks. The present invention may also be used in the fabrication ofworkpieces larger or smaller than 300 mm, such as for example 200 mm and150 mm. Moreover, while the present invention preferably operates withina FOUP system, it is understood that the present invention may operatewith other workpiece transport systems, including open wafer cassettesystems.

[0068] Unified Spine Structure

[0069] The spine structure 100 is based off the idea that a singleunified frame or structure may serve as a base foundation for an EFEM.This foundation may be repeatedly manufactured in a similar fashion soas to lower the cost of the system, and allow EFEM components to mountto the frame to simplify alignment. The structure or frame 100 minimizesthe amount of space required by a front end load tool. A frame orstructure also minimizes alignment time and greatly simplifies access tocomponents located inside the front end tool for maintenance proceduresand/or services that are required.

[0070] FIGS. 4-5 illustrate a preferred embodiment of the unified spinestructure 100. The spine 100 includes multiple vertical struts 102 thatare connected together by an upper channel or support member 104 and alower channel or support member 106. Each vertical strut 102 has aninward face 108 and an outward face 110. As shown throughout FIGS. 4-10,each vertical strut 102 preferably has a substantially rectangularcross-section. A rectangular cross section is preferred so that theoutward face 110 of each vertical strut 102 forms a seal with any EFEMcomponent mounted to the vertical strut 102. The rectangularcross-section of each vertical strut 102 also ensures that the uppersupport member 104 and lower support member 106 are flush against theinward face 108 and outward face 110 when secured to each vertical strut102. It is within the scope and spirit of the invention for the verticalstrut 102 to have a different cross section such as, but not limited to,circular or oval.

[0071] In the preferred embodiment, the spine structure 100 is comprisedprimarily of sheet metal components, with a few machine components wherethe precision is required. The sheet metal is implemented in ways whichtake advantage of the precision that can be derived from some aspects ofthis fabrication technique. For example, the long bends in the uppersupport member 104 and lower support member 106 that form a “U”-shapeprovide a very straight reference to align the vertical struts 102. In apreferred embodiment, holes 120 and 122 are punched in the upper andlower channel 104 and 106 to further guarantee good hole to holealignment between each vertical strut 102 and the upper and lowerchannel 104 and 106.

[0072] The sheet metal components also serve the function of exteriorskins or mounting surfaces (described hereinafter) to the system as wellas structural support. In current EFEM systems, sheet metal is usuallyreserved for non-structural panels which only provide cosmetic finishand containment. By incorporating sheet metal into several of thestructural components, the material cost of the EFEM may be dramaticallyreduced.

[0073] The upper support member 104 is secured to the top portion 114 ofeach vertical strut 102, while the lower support member 106 is securedto the bottom portion 112 of each vertical strut 102. Accordingly, thespine 100 provides a very straight and stiff structure in both torsionand bending to build a front end load system on. In a preferredembodiment, the upper support member 104 and the lower support member106 are manufactured from a single piece of sheet metal. The bends inthe sheet metal to create the upper support member 104 are dictated bythe width of the upper portion 114 of each vertical strut 102, so thatthe width of the “U”-shaped upper support member 104 is substantiallysimilar to the width of the upper portion 114 of each vertical strut102. Similarly, the width of the lower “U”-shaped support member 106 ispreferably substantially similar to the width of the bottom portion 112of each vertical strut 102. Each support member 104 and 106 is intendedto be flush against the inward face 108 and outward face 110 of eachvertical strut 102.

[0074] In a preferred embodiment, the lower portion 112 of each verticalstrut 102 is wider than the upper portion 114 of each vertical strut102. As best shown in FIGS. 4-5, the spine structure 100 aligns eachvertical strut 102 in a vertical orientation so that each vertical strut102 is substantially parallel to each other. Each strut 102 ispreferably spaced on 505 mm centers, which is the minimum allowedspacing for adjacent load ports per SEMI E-15.1. It is within the scopeand spirit of the invention for the vertical struts 102 to be spacedapart at various or unequal distances.

[0075] To provide a rigid structure in both a torsional and lateraldirection, each vertical strut 102 is secured to both the upper supportmember 104 and the lower support member 106. Each vertical strut 102 ispositioned between the upper support member 104 and lower support member106 as shown in FIG. 4. As previously described, each vertical strut 102is aligned with the mounting holes 120 and 122 in the upper supportmember 104 and the lower support member 106. By way of example only,each vertical strut 102 is secured to the upper support member 104 by abolt or pin secured to the top portion 114 of the vertical strut 102(e.g. through mounting hole 120), and at least one bolt or pin securedto the front face 110 or the back face 108. Each vertical strut 102 mustalso be secured to the lower support member 106. By way of example only,a bolt or pin is secured to the bottom portion 112 of each verticalstrut 102 (e.g. through mounting hole 122), and at least one bolt or pinis secured to both the front face 110 and the rear face 108.

[0076] The “U”-shaped configuration of the upper support member 104 andthe lower support member 106 further prevent each vertical strut 102from rotating in place. Although the upper channel 104 and lower channel106 as shown in FIGS. 4-5 are manufactured from a single piece of sheetmetal, it is within the scope and spirit of the invention for the uppersupport member 104 and lower support member 106 to be manufactured frommultiple pieces of material. In a preferred embodiment, and as bestshown in FIG. 5, the upper support member 104 and lower support member106 have a perforated surface. The perforated surfaces of the uppersupport member 104 and lower support member 106 allow air from afan/filter unit 150 (FFU) to flow through (see FIG. 10).

[0077] When the lower support member 106 is secured to the verticalstruts 102 it forms a front mounting surface 118 and a rear mountingsurface 116 that various EFEM components may mount to (see FIGS. 6-10).In general, the spine 100 creates at least three parallel and co-linearmounting surfaces: the front face 110 of the upper portion 112, thefront mounting surface 118, and the rear mounting surface 116. As willbe described later, the EFEM components mount to one of these threesurfaces. These three surfaces have a known spacial relationship betweenthem, and thus components mounted to these surfaces maybe aligned withminimal adjustments, or require no adjustments at all.

[0078] The lower support member 106 also creates an air flow area 121located between the front mounting surface 118 and the rear mountingsurface 116. The air flow area 121 is designed to accommodate a FOUPdoor open/close module 139 that has been guided away from the port dooropening and lowered down into the air flow area 121.

[0079] Isolating the FOUP door open/close module 139 from the area thewafer engine 300 operates within has many advantages. For example, asingle airflow generated by an FFU 150 is divided into two isolated airflows. One air flow will be directed towards the FOUP door open/closemodule 139, while a second separate air stream will be directed into thewafer engine area. The two isolated air flows will provide a cleanerenvironment for the FOUP/port door assembly 139 than if a single airflow was circulated for both the wafer engine area and the FOUP dooropen/close module 139. If there was only a single air flow path for boththe wafer engine 300 and the FOUP assembly 130 particles created by thewafer engine, 300 may contaminate the FOUP/pod door assembly 139.

[0080] The rear mounting surface 116 of the lower support member 106also operates as a protective barrier between the FOUP door open/closemodule 139 and the wafer engine area. The rear mounting surface 116prevents particles generated by the wafer engine 300 from entering theair flow area 121 storing the FOUP door open/close module 139. The rearmounting surface 116 also allows the wafer engine 300 to have localizedfiltering and exhaust systems that exhaust “dirty” air containingparticles below the wafer plane while not contaminate the FOUP dooropen/close module 139 (described hereinafter).

[0081] The spine structure 100 as shown in FIGS. 4-5 is configured as afour FOUP I/O port EFEM. It is within the spirit and scope of theinvention for the EFEM to include any number of I/O ports. Additionally,the EFEM may include spaces or blank I/O ports located between each I/Oport that wafers will be transported through. As previously mentioned,the spine structure 100 is scalable. The number of vertical struts 102,and the length of the upper support member 104 and the lower supportmember 106 may be modified to match the I/O port configuration requiredfor the EFEM.

[0082] Each vertical strut 102 also has a cam guide 124 machined intothe side surface. The cam 124 operates as a track or channel for guidingthe FOUP door open/close module 139 rearward away from the FOUP 10 andsubsequently downward into the air flow area 121. The movement of theport/pod door assembly 139 may be controlled by a motor assembly (notshown) located within the processing station. Such a motor assembly isknown in the art and does not require further disclosure. It is withinthe scope and spirit of the invention to mechanically guide and move theFOUP door 12 and port door 140 into the storage area 121.

[0083] The FOUP docking interface shown in FIGS. 6-7 illustrate severalEFEM components mounted to the spine structure 100. By way of exampleonly, the components may include a wafer engine or robot 300, a FOUPsupport assembly 130, a FOUP docking/isolation plate 138, and a portdoor 140. The FOUP support assembly 130 includes a FOUP advance support132, a FOUP advance module 133, and a FOUP support plate 134.

[0084] In order to transfer the workpieces from the FOUP 10 into themini-environment (see FIG. 10—“Class-1 Area”) a FOUP 10 is manually orautomatedly loaded onto the port advance plate 134 so that the FOUP doorfaces the load port door 140. A conventional load port door 140 includesa pair of latch keys which are received in a corresponding pair of slotsin the door latching assembly mounted within the FOUP door. An exampleof a door latch within a FOUP door adapted to receive an operate withsuch latch keys is disclosed in U.S. Pat. No. 6,188,323, entitled “WAFERMAPPING SYSTEM,” issued to Rosenquiest et al., which patent is assignedto the owner of the present invention, in which patent is incorporatedby reference herein in its entirety. In addition to decoupling the FOUPdoor from the FOUP shell, rotation of the latch keys also lock the keysinto their respective FOUP door slots. There are typically two latch keyand slot pairs, each of which pairs are structurally and operationallyidentical to each other.

[0085] A pod advance plate 134 typically includes three kinematic pins135, or some other registration feature, which mate within correspondingslots on the bottom surface of the FOUP 10 to define a fixed andrepeatable position of the bottom surface of the FOUP 10 on the advancedplate 134. Once a FOUP 10 is detected on the pod advanced plate 134, theFOUP 10 is advanced toward the port door 140 until the FOUP door lies incontact with or is near the port door 140. It is desirable to bring thefront surfaces of the respective doors into contact with each other totrap particulates and to insure a tight fit of the port door latch keyin the FOUP door key slot. U.S. patent application Ser. No. 09/115,414,entitled “POD DOOR TO PORT DOOR RETENTION SYSTEM,” by Rosenquist et al.,and U.S. patent application Ser. No. 09/130,254, entitled “POD TO PORTDOOR RETENTION AND EVACUATION SYSTEM,” by Fosnight et al. disclosesystems insuring a tight, clean interface between the FOUP 10 and portdoors. These applications are assigned to the owner of the presentinvention, and are both incorporated by reference herein in theirentirety.

[0086] Once the FOUP 10 and port doors are coupled, linear and/orrotational drives within the EFEM move the FOUP 10 and port doorstogether into the interior of the EFEM, and then away from the load portopening so that the workpieces may thereafter be accessible to the waferengine 300. As shown in FIG. 10, the port door 140 is affixed to theFOUP door and a controller actuates a slide to translate the carrier andport doors along the cam 124 located in each vertical strut 102. The cam124 guides the interlocked carrier and port doors vertically down intothe air flow area 121 of the lower support member 106. As previouslymentioned, the port door 140 and FOUP door are isolated from the rest ofthe Class-1 area while stored in the air flow area 121. The linear slideand rotational drive configurations (not shown) are known in the art anddo not require further disclosure. A linear slide may be comprised of alinear bearing and a drive mechanism. By way of example only, the linearbearing may include a ball or air bearing. Similarly, the drivemechanism may include a motor with a cam lead screw, a belt drive, or alinear motor. The rotational drive may be comprised of, by way ofexample only, a gear motor, a direct drive, a belt drive, or othersimilar means.

[0087] After the FOUP 10 and port doors are moved away from thedocking/isolation plate 138, the wafer engine or robot 300 may transferworkpieces into the tool front end without interference from the storedFOUP 10 and port doors. Once operations on a workpiece lot at the toolhave been completed and the workpieces have been returned to the FOUP10, the controller again actuates the drive and the slide to move thedoors back into the I/O port, where upon the FOUP door is transferredand secured to the FOUP 10.

[0088] The docking/isolation plate 138 is mounted to the front face 110of each vertical strut 102. The docking/isolation plate 138 isolates theinterior region (Class-1 or “clean” area) of the tool front end from theoutside ambient or exterior region. The docking/isolation plate 138 alsoprovides an interface plane that the FOUP 10 is advanced towards to aclose and controllable proximity (e.g., 0-5 mm separation). The plate138 forms an auxiliary seal with the FOUP 10 and the port door 140. Anauxiliary seal allows a separation to exist between the plate 138 andthe FOUP 10, but still creates an airtight seal between the plate 138and the FOUP 10. An airtight seal between the plate 138 and the FOUP 10is desirable to prevent gas from leaking out of the Class-1 Area or tomaintain the inert environment of the load port interface.

[0089] The docking/isolation 138 is preferably manufactured from asingle piece of material that includes one or more FOUP openingsmachined into it. The docking/isolation plate 138 includes registrationholes 144 to locate it accurately with respect to each vertical strut102. This provides a machined, precision relationship between all theFOUP 10 openings for the EFEM. The docking/isolation plate 138 may alsocomprise individual pieces of material that mount to each vertical strut102 using the same reference features. The plate 138 may be fabricatedfrom materials such as, but not limited to, plastic, metal, sheet metal,or even glass.

[0090] In a preferred embodiment, the docking/isolation plate 138 ismachined from a clear material, such as polycarbonate. Machining thedocking/isolation plate 138 from a clear material provides an addedbenefit of being able to see inside the mini-environment or Class-1 Areawhile the tool is in operation. The current E15 load port/SEMI E63 BoltsInterface does not define this feature. The docking/isolation plate 138does not have any structural features and therefore may be secured toeach vertical strut 100 of the spine 100 by only a few bolts and/orpins. Thus, the docking/isolation plate 138 may be easily removed.Further, since none of the EFEM components align with reference to thedocking/isolation plate 138, the docking/isolation plate 138 mayberemoved from the EFEM without disturbing the set up or alignment of theEFEM components such as the port door 140, the FOUP advance plate 134,or the wafer engine 300. This provides a simple method of gaining accessto the “clean” area (Class-1 area in FIG. 10) of the EFEM for service,maintenance, or error recovery.

[0091]FIG. 8 illustrates the wafer engine 300 mounted to the spinestructure 100. From this view, it is clearly shown that the wafer engine300 may travel linearly to access all the I/O ports of the EFEM. Thewafer engine 300 travels along a rail assembly 302, which is mounted tothe rear mounting surface 116 of the lower support member 106. In thisembodiment, the linear drive 302 is shown as a belt drive. It is withinthe scope and spirit of the invention for the linear drive 302 tocomprise other drive systems such as, but not limited to, a directdrive, a linear motor, a cable drive, or a chain link drive. Thecomponents of the wafer engine 300 will be described later. Such drivesystems are well known in the art and do not require further disclosure.

[0092]FIG. 9 illustrates further detail of the rail system 302 shown inFIG. 8 mounted to the spine structure 100. The rail system 302 includesan upper x rail 310, a lower x rail 312, and a carriage guide 311, allmounted to the rear mounting plate 118 of the lower channel 106. In apreferred embodiment, the upper x rail 310 and the lower x rail 312 arecircular or tubular, and are substantially parallel to each other.Engaging the upper x-rail 310, the lower x-rail 312, and the carriageguide 311 is an x carriage 304. The upper and lower x rail 310 and 312also serve as the main support for the wafer engine 300.

[0093]FIG. 9 also illustrates a control box 147 that is preferablylocated below the FOUP advance assembly 130. The EFEM requires manyelectrical control devices (e.g., control wiring, PCBs, etc.). It wouldbe an advantage if these devices were easily accessible for maintenanceand repair. The control box 147 provides an area to mount the electricaldevices. In a preferred embodiment, the control box 147 has a pivotingfront cover that may drop down for access to the electrical componentsinside. Within the control box are located many of the electricalcomponents and control systems required to power and operate the EFEMcomponents. It is intended that these electrical components maybe easilyaccessed for maintenance purposes and therefore the pivoting front coverof the control box 147 is secured by a few bolts and/or pins that may beremoved and allow the front cover to pivot downwards towards the floorof the fab.

[0094] As shown in FIGS. 10, and 30-31, the spine structure 100architecture provides a way to minimize the footprint of the EFEM andseal the clean volume of the system while still maintaining overallsystem accuracy. The FFU 150 mounts to and seals with the upper channel104 and a tool interface panel 154 to form the top of the EFEM. Thefront seal is provided by mounting the docking/isolation plate 138 tothe front face 110 of each vertical strut 102. A sheet metal panel 152,which is preferably a perforated surface, mounts to the lower supportmember 106 to form the bottom of the EFEM. The panel 152 also acts as anexhaust plate that allows the exhaust flow from both the FFU 150 and thewafer engine 300 to pass out into the ambient environment. Each side ofthe EFEM is sealed by end plates 156 which mount and seal with the spine100 (see FIG. 30), the tool interface panel 154, the panel 152, and theFFU 150. As shown in FIG. 10, the clean air flow from the FFU 150 andthe slide body FFU 420 travel through the mini-environment, or Class-1area, and out through the bottom panel 152 and the lower channel 106.The airflow exhausted from the Z slot fan 354 (described hereinafter),which contains particles generated by the vertical drive 380, alsotravels through the bottom panel 152. The airflow from the Z slot fan354 never enters the clean mini-environment.

[0095] In general, the spine 100 creates a single reference system tocalibrate and align the EFEM components, such as the wafer engine 300and the FOUP advance assembly 130. Each separate EFEM component maycalibrate to a known and fixed position, such as a vertical strut 102instead of calibrating and aligning with respect to each other. Thismethod of calibration is greatly simplified over the conventionalprocedures required today.

[0096] Spine Structure with a Backbone

[0097] FIGS. 11-13 illustrate another embodiment of a spine structure.The primary structural elements of this embodiment include a horizontalbeam 170, registration struts 172, and a front mounting plate 174. Asshown in FIG. 11, the horizontal beam 170 is preferably mounted to thebottom portion of each registration strut 172 to form a rigid frame. Thefront mounting plate 174 is also mounted to each registration strut 172,providing a surface for the exterior EFEM components (e.g., FOUP advanceassembly 130) to mount to. The horizontal beam 170 may be manufacturedfrom, by way of example only, an aluminum extrusion, steel tube, astructure made from bent sheet metal, a flat plate, a laminated plate,or most likely a combination of some of the above. The horizontal beam170 also provides a surface for the linear drive 306 (describedhereinafter) to mount to. Similar to the spine structure 100, thisembodiment provides a single reference to mount and align EFEMcomponents.

[0098]FIG. 12 illustrates that the FOUP door 12 and the port door 140are preferably still stored in an isolated area within the Class-1 Area.Accordingly, the beam 170 must be spaced apart from the registrationstruts 172 far enough to allow the FOUP door 12 and the port door 140 tofit between the beam 170 and the registration strut 172. As shown inFIG. 12, separators 171 are placed between each registration strut 172and the beam 170 to create the storage area. It is within the scope andspirit of the invention to create the storage area through other means.The beam 170 also functions as a protective barrier, preventingparticles created by the wafer engine 300 from contaminating the FOUPdoor 12 or the port door 140.

[0099]FIG. 13 illustrates that the support structure or spine mayinclude the beam 170 having a CNC milled aluminum plate 176 mounted tothe beam 170 for supporting the x-axis rails 310 and 312. This structureis further rigidified by a sheet metal U-shaped section 175. Thevertical registration struts 172, which are mounted to the section 175,are aligned similarly to the vertical struts 102 in the previousembodiment. As shown in FIG. 11, a front mounting plate 172 mounts tothe registration struts 174. EFEM components, such as the FOUP advanceassembly 130, mount to the front mounting plate 172.

[0100] The beam 170 may be positioned between the wafer engine 300 andthe pod openers below the work space of the wafer handler. The beam 170,however it is constructed, provides one structural common element thatthe EFEM components precisely mount to, eliminating the need for timeconsuming adjustments in the field when an EFEM is installed orreplaced.

[0101] Single Frame/Shell

[0102] FIGS. 14-16 illustrate yet another embodiment of the spinestructure configured as a FOUP docking station. In this embodiment, thespine structure that the EFEM components mount to is a single frame orshell 202. The frame 202 serves as a single reference for the interior,(e.g., engine wafer 300) and exterior components to mount to and alignwith (e.g., FOUP advance assembly 130) components similar to the spinestructure 100.

[0103] As shown in FIG. 14, the spine structure 200 includes three loadport assemblies 204 mounted to the frame 202. Each load port assembly204 is similar to the load port assembly 130 disclosed in the preferredembodiment. A load port door 206, which isolates the Class-1 area fromoutside ambient conditions, corresponds to each load port assembly 204for engaging and removing the FOUP door from the FOUP shell. It iswithin the scope and spirit of the invention for the frame 202 to havemore of fewer I/O ports. Similarly, the frame 202 may include afilled-in or solid I/O port located between I/O ports where wafers aretransferred through.

[0104] The frame 202 is preferably formed from a single piece ofmaterial. By way of example only, the frame 202 may be created by apunch press. The frame 202 may be manufactured from many differentmaterials. By way of example only, the frame 202 may be manufacturedfrom material such as, but not limited to, sheet metal, polypropylene,composites, or plastics. The frame 202 may also include an anodizedsurface finish to prevent or reduce outgassing. Whether the frame 202 ismanufactured from a single piece of material or separate parts, theframe 202 is scalable. Accordingly, the frame 202 may be customized tocreate as many FOUP I/O ports as necessary for the EFEM.

[0105]FIG. 15 illustrates several of the EFEM components mounted to theframe 202. The preferred embodiment of the frame 202, which ismanufactured from a single piece of stainless steel, is flexible. By wayof example only, the frame 202 may also be manufactured from an aluminumsheet. The EFEM must be rigid enough to provide accurate support andalignment points for the EFEM components. Additional supports 210 aremounted to the frame 202 to provide rigid and accurate support pointsfor components such as the linear drive 254, filter unit 220, FOUPadvance assembly 208, and tool interface plane.

[0106] To promote air flow through the load port interface, the topsurface 201 and the bottom surface 203 of the frame 202 are perforated.A fan/filter unit 220 maybe mounted to, and form a seal with, the topsurface 201 of the frame 202 to control the rate and quality of the airthrough the frame 202. Such fan/filter unit technology is well known inthe art and does not require further disclosure. A single fan/filterunit 220 may be appropriate to achieve the air flow rate desired.However, as the frame 202 increases in size and thus volume, the frame202 may require multiple fans to maintain the desired environmentalconditions. If the interior of the EFEM is not isolated from outsideatmospheric conditions (not an inert environment), air may be drawn intothe clean mini-environment by the FFU 220 and vented out through theperforated holes 212 in the bottom surface 203 of the frame 202.

[0107] If the EFEM is an inert system, a flow capture chamber 224 maybemounted to and sealed with the bottom surface 203 of the frame 202 sothat the air flow created by the fan/filter unit 220 is completelycontained and re-circulated. The end cap 210 may also have a flow returnpath guiding the air exiting the flow capture plenum 224 back to thefan/filter unit 220 for re-circulation.

[0108] Due to the minimal enclosed volume created by the frame 202 thepresent invention is a very efficient system from an air handlingstandpoint. A mini-environment with a smaller volume of air to controland filter makes it easier to maintain the cleanliness of the air. Inertsystems, or systems requiring molecular filters which degrade as moreair push through them, also benefit from a mini-environment containing asmaller volume of gas. By way of example only, filters will requirechanging less frequently if a smaller volume and rate of gas is passedthrough them.

[0109] System Volumetric Space Utilization

[0110] One of the key differentiators of all of the EFEMs previouslydescribed (e.g., spine structure, backbone, and frame) is thefundamental change in space utilization. The space utilization featurewill only be referenced to the spine structure 100 even though thisconcept applies to al the embodiments disclosed in this application. Inconventional tool front ends, the front end occupies all space from thefront of the load port (load face plane) to the process tool face, andfrom the floor of the fab up to its highest point, typically the top ofthe FFU and the full width of the front end.

[0111] An EFEM constructed from the spine structure 100 createssignificant space below the load ports 130, and the clean wafer enginearea maybe given back to the process/metrology tool or used for otherpurposes. Additionally, the overall depth of the enclosed area ormini-environment is also decreased from what conventional EFEMconfigurations require. The front of the wafer engine radial slide body400 may be rotated into the typically unused area for the FOUP doormechanism resides between the vertical struts 102. The space may begiven back to the process tool as well as the end user who may realizelower foot print requirements for the overall tool. The configuration ofthe wafer engine 300 takes advantage of these new and smaller spaceconstraints. For example, the radial slide 400 may reach further intothe process tool than a non-offset version.

[0112] As a result of the much smaller envelope of the system it isconsiderably lighter, and if mounted on the independent rolling frame,may be rolled away from the process tool to provide direct access to thetool. Since the system is also shorter than typical process tools, thespace above it may be used for other purposes as well, such as localFOUP 10 buffering for the AMHS system. With conventional overhead hoistAMHS systems, local buffer stations may only be placed between loadports or tools since they require unobstructed overhead path to the loadport. With the slide out shelf arrangement, the material could be storedin an otherwise unutilized area directly above the enclosed area of theintegrated EFEM.

[0113] As shown in FIGS. 30-31, the system may be integrated with theprocess tool in several ways. It is designed to require support at fourpoints. Two points in the front at the base of the two outer verticalstruts provide attached and leveling points. Two points at the rearlower corner of each end plate provide the rear support locations. Thesupport points could be provided by a roll out frame which would providean easy way to move the system away from the process tool. It could besupported by frame members from the process tool which could becantilevered out from the tool or supported from the floor. It mightalso be a combination of the two where the roll out frame could be usedto lift the system off kinematic points provided by the process toolframe.

[0114] Any of the integrated mini-environments and structures 100 or 200as previously described mount to the front of a tool associated with asemiconductor process. As used here, such tools include, but are notlimited to, process tools for forming integrated circuit patterns onsemiconductor wafers, metrology tools for testing various properties andwork pieces, and stockers for large scale storage of work piececarriers. As used herein, a tool may be simply an enclosure so that thework piece handling on the back side of the plate as describedhereinafter may be carried in an enclosed space. By way of example only,the structure 100 according to the present invention may comprise asorter for arranging and transferring work pieces with one or morecarriers.

[0115] Alternatively, the structures 100 may comprise a sorter or astandalone prealigner. In both the sorter and stand alone prealignerembodiments, the work piece operations are carried out entirely by theEFEM components mounted to the structure 100. The enclosure that formsthe Class-1 Area is also based from the structure 100 provides anenclosed, clean environment in which the work pieces maybe handled. Inseveral embodiments of the present invention, the structure 100 may beconsidered as being part of the tool (see FIG. 3A). In other embodimentsof the present invention, the system maybe affixed to but consideredseparate from the tool (FIGS. 29A-29D).

[0116] As best shown in FIG. 10, the FOUP docking station is formedaround the spine 100. A bottom pan 118 is secured to, and forms a sealwith, the bottom support member 106. In a preferred embodiment, thebottom pan 118 is perforated surface to allow air from the FFU 150 topass through. The FFU 150 is secured to, and forms a seal with, theupper support member 104. A wafer transfer plate 122 is secured to, andforms seal with, the bottom pan 118 and the FFU 150. The wafer transferplate 122 may include transfer windows 121 that allow the wafer engine300 to transfer wafers between the Class-1 Area and the process tool.

[0117] The system forms an air tight seal to maintain the Class-1environment. An air tight seal is created between both the spine 100 andthe bottom pan 118, the spine 100 with the FFU 150, and the wafertransfer plate 122 with both the FFU 150 and the bottom pan 118.Generally, the pressure within the Class-1 Area is maintained at a levelhigher than that of the atmosphere surrounding the Class-1 Area. Thispressure differential prevents unfiltered air from entering the Class-1Area. Accordingly, airborne particles or contaminates are blown out ofthe Class-1 Area through the openings in the bottom pan 118. On occasiontools operate in a hostile environment, such as for example, a purenitrogen environment. In such an environment it is necessary tocompletely isolate the Class-1A Area from the outside surroundingenvironment. A plenum may be secured to, and sealed with, the bottom pan118, so that the mini-environment within the structure 100 is completelyisolated from atmospheric conditions. A plenum 224 (see FIG. 14) may bemounted to the bottom pan 118 to capture the air and recirculate it backtowards the fan/filter unit 150 mounted to the spine 100.

[0118] Wafer Engine

[0119] In general, the wafer engine 300 illustrated in FIGS. 18-23minimizes mechanical inertias with respect to frequency of use andcriticality of wafer transfer cycle time. By way of example only, someof the benefits resulting from this wafer engine 300 include (1)achieving faster wafer swap times, (2) a lower total system weight, and(3) a more compact, unified package. The wafer engine 300 may operatewithin any of the embodiments of the unified spine 100 disclosed in thisapplication, or operate as a stand-alone device.

[0120] A preferred embodiment of the wafer engine 300 is illustrated inFIGS. 18-19. The wafer engine 300 includes four main coordinated drivesto optimize the transfer of wafers within the EFEM. The four drives movea wafer along an x-axis, a theta axis, a z-axis, and a radial or r axis.

[0121] The wafer engine 300 has a linear drive assembly 302 that movesthe wafer engine 300 along an x-axis. Movement along the x-axis allowsthe wafer engine 300 to access each FOUP I/O port. The linear driveassembly 302 includes an x-carriage 304 and a rail system 306. Thex-carriage 304 slidably engages the upper x-rail 310 and lower x-rail312. The rail system 306 is mounted to the rear mounting plate 116, andincludes an upper x-rail 310 and lower x-rail 312. The upper x-rail 310and lower x-rail 312 extend along the x-axis and are substantiallyparallel to each other. The break lines running through the railassembly 306 in FIG. 18 shows that the rail assembly 306 may be of anylength. The rail assembly 306 is scalable so that the wafer engine 300may travel along the rail assembly 306 to access, for example, thewafers stored in each FOUP 10. The rotational drive 350 of the waferengine 300 is also mounted to the x-carriage 304. Thus, movement by thex-carriage 304 drives the wafer engine 300 along the x axis.

[0122] The wafer engine 300 may also rotate, pivoting about a theta (θ)axis. In a preferred embodiment, and as shown in FIG. 18, the rotationaldrive 350 includes a support column 364 that extends along the thetaaxis and mounts to a z-axis support 370. The rotational drive 350includes a theta motor 362 to drive and rotate the support column 364.The rotational drive 350 may rotate in either a clockwise orcounterclockwise direction. The rotational drive 350 may also mountdirectly to the vertical drive 380. Preferably, the theta axis does nottravel through the center of the slide body 400. The advantages of thisoff-center configuration of the slide body 400 will be discussed later.

[0123] The rotational drive 350 further includes a fan extensionplatform 352. In a preferred embodiment of the wafer engine 300, and asshown in FIG. 20, a z slot fan 354 is mounted to the underside of thefan platform 352. This configuration of the wafer engine 300 locates thez slot fan 354 near the theta motor 362 and provides and air vent toexhaust the air driven through the z column 380 of the wafer engine 300.The air flushed through the z column 380 is projected downward, awayfrom any wafer that is being transported by the wafer engine 300 (seeFIG. 21). Alternatively, the airflow may be exhausted through, and outthe bottom of, the rotational drive 350.

[0124] The vertical drive column 380 is mounted to the support member370 and extends upward along the z-axis. The drive column 380 moves theslide body 400 (described hereinafter) of the wafer engine 300, and thusthe wafer, up and down along the z-axis. In one embodiment, and as shownin FIG. 19, the drive column 380 is an elongated column that extendssubstantially perpendicular from the support member 370. A driveassembly is located within the drive column 380 and includes a z-drivemotor 382, a z cable way 384, a z guide rail 386, and a z ball screw388. Such drive means are well known in the art and do not requirefurther disclosure. It is within the scope and spirit of the inventionto move the slide body mechanism 400 by other means.

[0125] The slide body 400 preferably includes an upper end effector 402and a lower end effector 404 for quickly swapping individual wafersalong the r-axis. The slide body 400 supports the upper and lower endeffectors 402 and 404 such that they are parallel to the wafers storedin each FOUP 10. As shown in FIG. 19, the upper end effector 402 andlower end effector 404 travel along a similar rectilinear path. Theupper end effector 402 and lower end effector 404 are separated by adistance sufficient to allow the lower end effector 404 and the upperend effector 402 to simultaneously store wafers. The slide body 400includes radial drive motors 410 for moving the upper end effector 402and lower end effector 404 linearly along the radial or r-axis.

[0126] The upper end effector 402 is supported by an first support 406and the lower end effector 404 is supported by a second support 408. Theupper end effector support 406 and lower end effector support 408 eachslidably engage and travel within a radial guide rail 410 that extendssubstantially across the length of the slide body 400. Each radial drivemotor 410 drives a radial drive belt 414. The radial drive belt 414 a isconnected to the first support 406, and the second radial drive belt 414b is connected to the second support 408. The radial drive motor 410 mayrotate in a clockwise or counter-clockwise direction to rotate theradial drive belt around a radial drive pulley 416 and an end idlerpulley 418 and to extend and retract the respective end effector. Such adrive mechanism is well known in the art and does not require furtherdisclosure. It is within the scope and spirit of the present inventionto have other means to move a wafer along the radial or r-axis.

[0127] The wafer engine 300 has many moving parts. Moving parts tend tocreate particles. For example, the continual extension and retraction ofthe upper end effector 402 and lower end effector 404 will createparticulates within the mini-environment. To prevent the particulatesfrom contaminating the wafer located on either end effector, a slidebody fan/filter unit (FFU) 420 is mounted to the underside of the slidebody 400. The slide body FFU 420 continuously pulls air in through theslide body slide slots 420, pulls the air through the slide body 400,filters the air, and then exhausts the air out into the Class-1 Area.This localized filtering of the air flow greatly reduces the amount ofparticles placed into the Class-1 Area.

[0128] Conventionally, most mini-environments include a singlefan/filter unit that circulates the air through the mini-environment andonly filters the air flow as it flows into the EFEM. Any particulatescreated within the mini-environment downstream of the fan/filter unitremain in the clean area until they are exhausted out of the EFEM. It isdesirable to minimize the number of particulates within themini-environment especially since the trend in semiconductormanufacturing more and more requires a lower tolerance of particlecontamination on the wafers.

[0129] The localized filtering of the wafer engine 300 removes particlescreated by any rotating or sliding mechanism located on the wafer engine300 as the particle is created. In a preferred embodiment, and as shownin FIGS. 19 and 21, a local fan/filter unit or fan system is locatedapproximate to both linear drives of the z column 380 and slide bodymechanism 400. As specifically shown in FIG. 21, the fan/filter unitmounted to the slide body mechanism 400 exhausts filtered air into theclean mini-environment, while the z slot fan system of the verticaldrive 380 exhausts unfiltered air through the bottom plate of the EFEM.The wafer engine 300 filters and exhausts air into the Class-1 Area ofthe EFEM. If the wafer engine 300 did not have the fan/filter mounted tothe slide body mechanism 400, particles created by the slide bodymechanism 400 would travel through the Class-1 Area and contaminate thewafer supported by either end effector.

[0130]FIG. 20 illustrates another embodiment of the wafer engine 300. Inthis embodiment, the slide body 400 engages the z column 380 such thatthe z column 380 is substantially along the r axis. Similar to previousembodiments of the wafer engine 300, this embodiment includes a thetamotor 362, a vertical drive column 380 and a radial slide body 400. Thetheta motor rotates the wafer engine about the theta axis, the z columnmoves the radial slide body 400 linearly along the z axis, and theradial slide body 400 moves the end effector 401 along the radial orr-axis. Accordingly, the wafer engine and thus the wafer will rotateabout the theta axis any time the theta motor 362 rotates. Thisembodiment may also include a fan/filter unit mounted to the radialslide body 400 in a v slot fan similar to the previous embodiment of thewafer engine 300.

[0131] As previously mentioned, the slide body 400 of the wafer engine300 may include different configurations of end effectors. Asillustrated in FIGS. 18-19, the upper and lower end effector 402 and 404may include a passive edge support. Such a configuration is known in theindustry as passive edge grip end effectors for 300 mm wafers. FIG. 22illustrates that the upper end effector 402 may include an active edgegrip, while the lower end effector 404 may include a passive edgesupport. Alternatively, the end effectors 402 and 404 may include anycombination of, for example, a vacuum grip with backside contact, areduced contact area, removable pads.

[0132] Similarly, the radial drive 400 may include different types ofend effector for handling wafers at different stages. For example, oneend effector may handle only “dirty” wafers, while the second endeffector may handle only “clean” wafers. Alternatively, one end effectormay be designated to align and read the wafer ID before transferred tothe process tool, while the second end effector may include hightemperature pads for handling hot wafers after being processed.

[0133] Integrated Tools in Wafer Engine

[0134] A conventional wafer handling robot transports individual wafers,for example, from a FOUP 10 to a separate processing station. Theprocessing station inspects or aligns the wafer and then the waferhandling robot may transport the wafer to the next station. Often thewafer handling robot must sit idle or return to a FOUP 10 to transport asecond wafer while the process station operates. Such an operationreduces the throughput of the system.

[0135] In one embodiment, the wafer engine 300 includes a slide body 400that may perform one or several of these functions normally performed ata separate processing station. Integrating one or several of thesefunctions into the slide body 400 will increase the throughput of thesystem and reduce the footprint of the EFEM.

[0136] FIGS. 22-23 illustrate a wafer engine 300 equipped with a wheeledaligner 440 and ID reader 430 mounted on the slide body 400. Thisembodiment is similar to the wafer engine 300 as shown in FIGS. 18-19,with the addition of a wheeled aligner 440 mounted on the upper endeffector 402, and an ID reader 430 mounted to the slide body 400. It iswithin the spirit and scope of the invention for the lower end effector404 to include a wheeled aligner.

[0137] The ID reader 430 may view up or down for reading marks on topand/or the bottom surfaces of the top or bottom of the wafer. It iswithin the scope and spirit of the invention for the ID reader 430 to bemounted to the vertical drive 380, or be mounted in a fixed locationelsewhere on the wafer engine 300. IN the preferred embodiment, it isadvantageous to mount a top side ID reader 430 on the slide body 400 forfast ID reading. A second ID reader may be mounted at a fixed locationelsewhere in the EFEM for reading the bottom side T7 mark forconfirmation or clarification of wafer ID if required.

[0138] If ID reading is required but wafer orientation is not important,the aligner may be eliminated and the ID reader 430 may view the ID markin whatever location the wafer arrives on the end effector. Tofacilitate this operation, the ID reader 430, or a mirror assembly, maybe rotated above the surface of the awfer to view the ID mark. Thiseliminates the need to rotate the wafer for ID reading and thus improvescleanliness and throughput.

[0139] An aligner controls the rotation of the wafer about an axis, suchas by wheel or other means. FIGS. 23-24 illustrate one embodiment of anend effector with a wheeled aligner 440. The wheeled aligner 440includes a drive system 449 and a paddle plate 442. The paddle plate 442is the main support for the wafer. Located at the end of the paddleplate 442 are two sets of passive tip wheels 446 and two pads 448. Thewheels 446 and pads 448 support the wafer at different times duringalignment. A drive wheel 450, located at the back end of the paddleplate 442, supports the wafer along a third contact surface while thewafer is being aligned.

[0140] In one embodiment, wheeled end effector 440 slides underneath awafer located in a FOUP 10 and is raised until the wafer is supported bythe pads 448. The pads 448 preferably only support the wafer along itsbottom edge. To align the wafer, the wafer is pushed forward by thedrive wheel 450 and up onto the wheels 446. The wafer is lifted off thepads 448 and is fully supported by the drive wheel 450 and the tipwheels 446. At this point the drive wheel 450 may rotate to spin thewafer in situ. This operation may be performed while the wafer engine300 is transporting the wafer. The wafer engine 300 does not have toremain in place to align the wafer.

[0141] Alternatively, as shown in FIG. 26B, the slide body 400 mayinclude a vacuum chuck aligner 411. The drive mechanism for the vacuumchuck aligner 411, including a lift and rotation axis, may reside insidethe slide body 400. A sensor 409 may be mounted to the end effector 403to locates the edge of the wafer while it remains on the end effector.The sensor 409 may also be mounted to an structure that is independentof the end effector 403. In general, the sensor 409 may be located atvarious locations as long as the sensor 409 can be positioned to readthe top surface of the wafer.

[0142] The edge position may be mapped relative to the rotation angle tofind the center and orientation of the wafer. The sensor 409 functionsas a secondary feedback device. The location of the sensor 409 is knownrelative to the wafer at all times. Thus, the sensor 409 may send errorsignals indicating that the wafer is not aligned. Since the alignerreceives additional error data from the sensor 409, an aligner with sucha sensor will improve the accuracy of the aligner. The wafer can then bereoriented by the chuck 411 and placed on center at the next drop offstation by the wafer engine 300.

[0143] The sensor 409 may be mounted independently within the EFEM andbe a separate component from the wafer engine 300. In such aconfiguration, the wafer is placed on the chuck 411 that can rotate. Thesensor 409, mounted on a mechanism that has position control andmeasuring means (not shown), is moved to the proximity of the wafer edgeuntil the sensor signal is at a desired level. The wafer can then berotated while the sensor mechanism uses the signal from the sensor 409to keep the position of the sensor 409 at the this desired level,effectively keeping the sensor 409 at the same relative position to thewafer edge. As the wafer is rotated, the sensor position is recordedwith respect to the angular position of the wafer. This data representsthe change in radial position of the wafer edge with respect to waferrotational position, and can be used to calculate the center of thewafer with respect to the center of the wafer chuck and the orientationof the fiducial. If the sensor signal magnitude is also recorded alongwith the sensor mechanism position, it can provide additional edgeposition information that could improve the accuracy of the wafer centercalculations or fiducial orientation.

[0144] The wheeled end effector aligner 440 may include other componentssuch as, but not limited to, an optical notch sensor 452 to detect thenotch along the edge of the wafer. For example, once the notch has beenlocated along the edge of the wafer by the optical notch sensor 452 thedrive wheel 450 may rotate the wafer to the desired position and retractback, allowing the wafer to fall back down onto the pads 448. Thisoperation may be performed while the end effector is in place or ismoving. The ability to align the wafer while it is being transferredbetween FOUPs 10, or between a FOUP 10 and a processing tool, greatlyreduces or eliminates the amount of time that an end effector must sitidle. Further, there is no need for a separate processing station if thewafer engine 300 can align a wafer “on-the-fly.”

[0145] The slide body 400 enables a stable mounting platform for avariety of auxiliary functions, measurements, and sensors to acquirevarious wafer data. By way of example only, components may be integratedinto or mounted to the slide body 400 to detect a wafer edge, detect thenotch location on the wafer, read the OCR/bar code, perform particulatecounting (back side or front side), determine film thickness/uniformityor circuit element line width, and detect resistivity (via contactprobes or non-contact means) and wafer thickness. Other processes knownin the art for inspecting and marking a wafer may be incorporated intothe slide body 400.

[0146] In order to transfer workpieces from a carrier, the end effectors402 and 404 move horizontally under the workpiece to be transferred andthen moved upward to lift the workpiece off its resting place. The endeffectors 402 and 404 may also include edge grips for supporting theworkpiece at its edges. Alternatively, the end effectors 402 and 404 maybe a blade type end effector for supporting a workpiece by its bottomsurface. In such embodiments, a vacuum source (not shown) may be affixedto or remote from the paddle plate 442, which creates a negativepressure that is communicated through the workpiece handling robot viaflexible vacuum tubes to the surface of the end effector blade. Uponactivation of the vacuum source a negative pressure is formed at thesurface of the end effector blade, creating a suction capable of holdinga workpiece firmly thereon. A vacuum sensor (not shown) of knownconstruction may also be provided on the robot and associated with thevacuum system for detecting when a workpiece is engaged with the endeffector and restricting the pull of air through the vacuum tubes. It isunderstood that the present invention is not limited to the end effectordescribed above and that a variety of end effector designs may be usedas long as the end effector has the capability to pick up and drop offworkpieces.

[0147] The slide body 400 may also be adapted to process a wafer andenvironmentally isolate the wafer from the Class-1 Area. By way ofexample only, the slide body 400 may include process tools to eitherheat or cool the surface of the wafer, or conduct thermal surfaceprocessing. In another embodiment, the slide body 400 may include ahousing (not shown) that a wafer may be retracted into and temporarilystored within while the wafer engine 300 is transferring the wafer outof the process tool and within the Class-1 Area. The housing provides aninert or clean environment that has a better than Class-1 Areaenvironment. Such a system may include floating oxygen or an inert gasover the surface of the wafer while it is being transported.

[0148] Dual Swap Capability

[0149] The time between when a processed wafer is removed from theprocess station and when a new wafer is placed into the process stationis known as the “swap time.” For most process tools, the throughput isdetermined by the process time plus the swap time. Reducing eitherincreases throughput. The process time is the purview of the toolmanufacturer, the swap time is the purview of the capital EFEMmanufacturer.

[0150] For a conventional single end effector wafer handling robot in anEFEM (see FIG. 17), the swap time maybe 8 to 16 seconds, depending onthe station arrangement and the speed of the wafer handling robot. Thefollowing sequence of operations are commonly used by such a robot toswap a wafer at a process station. The items contributing to the swaptime are in italics. Items outside of the critical path determiningthroughput are in (parenthesis).

[0151] 1. Get wafer from process station

[0152] 2. Put processed wafer to load port

[0153] 3. Get aligned wafer from aligner

[0154] 4. Put aligner wafer to process station

[0155] [Begin Processing Wafer]

[0156] 5. (While processing, robot get new wafer from load port)

[0157] 6. (While processing, robot put new wafer to aligner)

[0158] 7. (While processing, aligner align wafer)

[0159] [Repeat]

[0160] A rapid swap robot (e.g. wafer engine 300) has two end effectorsand therefore can dramatically reduce swap time by performing the samefunction as above using the following abbreviated sequence:

[0161] [Process Complete]

[0162] 1. Get wafer from process station with paddle 1

[0163] 2. Put aligned wafer to process station with paddle 2

[0164] [Process Wafer]

[0165] 3. (While processing, get new wafer from load port)

[0166] 4. (While processing, put new wafer to aligner)

[0167] 5. (While processing, aligner align wafer)

[0168] 6. (While processing, get aligned wafer from aligner)

[0169] [Repeat]

[0170] In this case, the swap time may be reduced by 3 to 6 secondsdepending on the speed of the robot. The overall time for the robot tocomplete all of its motions may be slightly reduced as well. The overallmotion time is of primary importance in applications where the processtime is very low and therefore the items in parenthesis above wouldenter into the critical path or throughput.

[0171] A further improvement on throughput and reduction in total robotmotions can be made if the robot has align-on-the-fly capability as wellas rapid swap capability like the wafer engine 300 having a wheeled endeffector aligner 440. Align-on-the-fly does not reduce swap time, but itdoes reduce overall robot motion time and therefore increases throughputwhere the process time is low, or where the robot must support multipleprocess stations. Also, by reducing the number of robot motions andwafer handoffs, align-on-the-fly can increase robot life and improvecleanliness.

[0172] For the align-on-the-fly rapid swap wafer engine, the comparablesequence of operations is:

[0173] [Process Complete]

[0174] 1. Get wafer from process station with paddle 1

[0175] 2. Put aligned wafer to process station with paddle 2

[0176] [Process Wafer]

[0177] 3. (While processing, get new wafer from load port)

[0178] 4. (While processing, align wafer and simultaneously move toposition for next rapid swap)

[0179] [Repeat]

[0180] Unlimited Z-Axis Motion

[0181]FIG. 25 illustrates a wafer engine 300′ including an off-centerslide body 400 having a wheeled aligner 454 and ID reader 430, and anextended z-axis drive column 380′. This embodiment of the wafer engineincludes an extended z column 380′ to, for example, to access a stocker,or a load port or process station that may be located above the FOUP I/Oport. Basically, the height of the z-axis drive column 380 or 380′ isunlimited. The wafer engine 300 or 300′ may access a wafer locatedwithin a FOUP 10 by moving the upper end effector 402 or the lower endeffector 404 along the radial or r-axis. The distance that the upper endeffector 402 or lower end effector 404 must travel into the FOUP 10 isdesigned to be a short distance since this is the most often requiredmotion of the wafer engine 300 or 300′. The height of the vertical drivecolumn 380 or 380′ does not effect the distance that either the upperend effector 402 or lower end effector 404 must travel. Thus, the heightof the vertical drive column 380 or 380′ does not effect the motionalong the radial or r-axis.

[0182] Conventional wafer handling robots must move the z drive columnlinearly towards the FOUP 10 so that the end effector may access andremove the wafer from the FOUP 10. Accordingly, a tall vertical drivecolumn for such a wafer handling robot requires moving a large verticalcolumn by a motor or a belt drive. Moving such inertia places greatstrain on the wafer handling robot. The wafer engines disclosed in thisapplication are an improvement over such wafer handling robots becausethe axis of motion, along the radial or r-axis, which is the mostcommonly traveled are also the shortest distances.

[0183]FIG. 27A illustrates that a conventional linear slide robot mayreach into the processing tool 250 mm for transferring and retrievingwafers into the process tool. Similarly, a convention wafer handlingrobot requires a minimum clearance within the EFEM work space of 520 mmso that the wafer handling robot can maneuver within the EFEM. FIG. 27Billustrates the reach and swing clearance advantage of the off-centerslide body rotation about the theta axis. In a preferred embodiment, theoff-center slide body axis of rotation, shown as the theta axis in FIG.19, is offset by approximately 50 mm. The off-center axis of rotationfor the wafer engine 300 has two distinct advantages. First, the maximumreach of an end effector (e.g., upper end effector 402 or lower endeffector 404) into the processing tool is increased to 350 mm. Second,the minimum clearance required within the EFEM work space is reduced to420 mm. The maximum reach and minimum clearance distances are by way ofexample only. Increasing the reach of the end effector into the processtool, while decreasing the minimum clearance required for the waferengine 300 to maneuver within the EFEM reduces the overall footprint ofthe EFEM.

[0184]FIG. 28 illustrates an example motion sequence of the wafer engine300 having a rapid swap slide body 400 with off-center rotation axis. Byway of example only, step one illustrates the wafer engine 300 liftingthe wafer at load port area one. Step two illustrates the wafer engine300 retracting the wafer from within load port one along a radial axis.Step three illustrates the wafer engine 300 rotating about the thetaaxis and simultaneously moving back along the x-axis to avoid collisionwith load port one. Step four illustrates the wafer engine 300 movingalong the x-axis towards the I/O port of the processing station. Stepfive illustrates the wafer engine 300 continuing to rotate about thetheta axis and along the x-axis to position the wafer for entry into theprocessing station. Step six illustrates the wafer engine 300 waitingfor the process to complete. Step seven illustrates the wafer engine 300swapping the processed wafer for the new wafer ready to enter theprocessing station. Finally, step eight illustrates the wafer engine 300retracting the processed wafer in a radial axis while simultaneouslymoving along the x and theta axis to return the processed wafer intoload port one, two or three.

[0185] The wafer engine 300 and 300′ described above provides severalbenefits over conventional wafer handling robots. For most waferhandling applications, radial motion needed to insert and remove wafersinto and out of a FOUP 10 or a process station has the highest dutycycle and longest overall distance traveled. The wafer engine 300 placesthe radial drive 400 as close to the wafer as possible before attemptingto access the wafer. This placement reduces the moving mass and motiontime of the upper end effector 402 and lower end effector 404, and wear.

[0186] The z-drive column 380 occupies the same volume of space that isswept out by the wafer as the wafer engine 300 rotates. The drive column380 also does not extend below the work plane. A conventional waferhandling robot must utilize the area located below the wafer plane toaccess some of the wafers within the FOUP 10. Typically, the endeffector is mounted to the top of a column that travels up and downalong the z axis. The column takes up space that could otherwise be usedfor other purposes. Similarly, when the column moves horizontally alongthe x axis, the area located below the wafer plane must substantiallyempty so that the column does not run into and damage any obstacles.

[0187] There are several variations and/or modifications that can bemade to the wafer engine 300 that still have the unique elements andbenefits previously listed above. By way of example only, the x-axisdrive 302 may be eliminated for some applications. Similarly, a singleradial axis may suffice. Further, for some applications (e.g., sorters)may not require a rotational drive. Instead, the z-axis drive 380 wouldmount to the x-carriage 308. A sorter application, for example, may haveall of the load ports mounted facing the same direction, and if thealignment and ID reading is integrated into the wafer engine 300, theneed to rotate would be eliminated.

[0188] FIGS. 29-31 illustrate several configurations of the integratedsystem. FIG. 29A illustrates the integrated system mounted on a roll outframe. As previously mentioned, conventional EFEMs extend all the waydown to the floor of the wafer fab. With the space savings derived fromconstructing an EFEM from a spine structure 100 or other embodimentsdisclosed in this application, the footprint of the integrated system isgreatly reduced. As shown in FIG. 29A, the integrated system is mountedon a roll out frame so that the load port assemblies remain at the SEMIstandard height of 900 mm. When this integrated system is bolted to thefront end of a processing tool, and in a preferred embodiment, therewill be approximately 2 feet of open space located beneath theintegrated system and the wafer fab floor. This space has never beenavailable in a wafer fab before. Such a space will allow semiconductormanufactures to place other items such as an electrical control boxunderneath the integrated system.

[0189] Alternatively, a processing tool may now have a maintenanceaccess that can be reached by crawling underneath the integrated system.The roll out frame also improves the overall maintenance features of theprocessing tool that the integrated system is bolted to. By way ofexample only, if maintenance needs to be performed on the processingtool, the integrated system may be unbolted from the processing tool,the wheels of the roll out frame may be unlocked, and the integratedsystem may be rolled away from the front end of the processing tool. Aconventional EFEM that is bolted to the processing tool does not containwheels that the EFEM can be rolled out on, and is typically such a heavydevice that it requires more than one maintenance person to lift theEFEM away from the process tool. As previously mentioned, the integratedsystem of the present invention weighs only several hundred pounds andthus can be easily rolled away from the front of the processing tool bya single maintenance person.

[0190] FIGS. 30 illustrates the integrated system integrated into aprocess tool. By way of example only, the system of the presentinvention may be integrally formed and mounted to a process tool. Oneadvantage of this system is that if every process tool within the waferfab had an integrated system mounted to it, the wafer fab would have afront and load system that can be configured to the needs of eachprocess tool yet contain a similar environment to reduce the need forstocking spare parts and training maintenance personnel.

[0191] Electrical Control System

[0192] Conventional EFEMs must contain a power distribution that iscompatible with the power requirements for countries across the world.Therefore, most EFEMs today must be able to adapt to either a 110V or a220V system. Being able to a adapt to either power system requires thatan EFEM include power components such as step down or step uptransformers as well as other electrical components. Such electricalcomponents must be mounted within the EFEM and thus increase thefootprint of the EFEM.

[0193] The EFEM of the present invention is designed for all electricalcomponents such as the FOUP advance plate assembly, the wafer engine 300and the fan/filter unit 150 to operate all under a 48V system. Ingeneral, the EFEM of the present invention may be electrically connectedto either a 110V or 220V system that will stepped-down to 48V to controlall of the elements described previously. Simplifying the electricaldistribution system of the EFEM eliminates the need for many of theconventional power distribution components such as the step uptransformer and thus further decreases the footprint of the EFEM of thepresent invention.

1. A unified frame that semiconductor front end components may mount to,the unified frame providing a single reference for all the components toalign with, comprising: at least two vertical struts, each said verticalstrut having an upper portion, a lower portion, a front face, and a rearface; an upper support member secured to said top portion of each saidvertical strut; a lower support member secured to said lower portion ofeach said vertical strut, said lower support member creating a frontmounting surface that is secured to said front face, and a rear mountingsurface that is secured to said rear face; and the front end loadcomponents mount to said front and rear mounting surface.
 2. The unifiedframe as recited in claim 1, wherein said lower support member furthercreates a port door/carrier door storage area located between said frontmounting surface and said rear mounting surface.
 3. The unified frame asrecited in claim 1, wherein said upper support member has at least oneperforated surface.
 4. The unified frame as recited in claim 1, whereinsaid lower support member has at least one perforated surface.
 5. Theunified frame as recited in claim 1, wherein each said vertical strut issubstantially parallel to each other.
 6. A unified frame thatsemiconductor front end components may mount to, the unified frameproviding a single reference for all the components to align with,comprising: at least two vertical struts, each said vertical struthaving an upper portion, a lower portion, a front face, and a rear face;an upper support member secured to said top portion of each saidvertical strut; a lower support member secured to said lower portion ofeach said vertical strut, said lower support member creating a frontmounting surface that is secured to said front face; and the front endload components mount to said front mounting surface of said lowersupport member and said rear face of said vertical strut.
 7. The unifiedstructure as recited in claim 6, wherein said upper support member hasat least one perforated surface.
 8. The unified structure as recited inclaim 6, wherein said lower support member has at least one perforatedsurface.
 9. The unified structure as recited in claim 6, wherein eachsaid vertical strut is substantially parallel to each other.
 10. Aunified frame that semiconductor front end components may mount to, theunified frame providing a single reference for all the components toalign with, comprising: at least two vertical struts, each said verticalstrut having an upper portion, a lower portion, a front face, and a rearface; an upper support member secured to said top portion of each saidvertical strut; a backbone support member secured to said rear face ofeach said vertical strut, a front mounting plate secured to said frontface of each vertical strut; and the front end load components mount tosaid front mounting plate and said backbone support member.
 11. Aunified frame that semiconductor front end components may mount to, theunified frame providing a single reference for all the components toalign with, comprising: at least two vertical struts, each said verticalstrut having an upper portion, a lower portion, a front face, and a rearface; a component mounting surface having an I/O port, said componentmounting surface secured to said top and lower portion of each saidvertical strut; and the front end load components mount to saidcomponent mounting surface and said rear face of said vertical strut.12. A unified frame that semiconductor front end components may mountto, the unified frame providing a single reference for all thecomponents to align with, comprising: at least two vertical struts, eachsaid vertical strut having a first mounting surface, a second mountingsurface, and a third mounting surface, said first, second, and thirdmounting surface being parallel to each other; and the front end loadcomponents mount to at least one of said first, second, and thirdmounting surface of said vertical strut.